This invention relates to collision damage avoidance systems for aircraft.
Collisions on the ground at airports, especially on crowded runways, are increasingly frequent. Equipment to sense the presence of other aircraft is expensive and difficult to install on existing, crowded aircraft.
Systems external to aircraft exist, such as a traffic control system at Dallas-Fort Worth International Airport which shows red lights indicating that aircraft should stop, and green for go.
Various taxiing guidance systems within aircraft are disclosed in the art. The degree of automation in taxiing may vary. The degree to which such guidance systems are used to avoid collision or track the location of other aircraft is limited, as is the ability to install such equipment in existing aircraft.
U.S. Pat. No. 6,411,890 to Zimmerman discloses a method for the guidance of aircraft on the taxiways of the airport apron with position lights located on the taxiways and, possibly, other locations on the apron. It comprises the following components: a navigation system to determine the current aircraft position; a sensor on the aircraft to detect position and measure lights, reference information including light positions, a comparison of the path pursued by the navigation system with the reference information, and using the detected lights as waypoints for the navigation system.
U.S. Pat. No. 6,690,295 to De Boer teaches a device for determining the position of an aircraft at an airport, including sensors for detecting radio signals originating from a vehicle. The sensors are positioned at regular intervals from one another on parts of the airport which are accessible to the vehicle. The sensors are fitted in light positions of runway lighting provided at the airport on taxiways, take-off and landing runways and on platforms. The signal originating from a radio altimeter of an aircraft is used as the radio signal. Data communication takes place from the sensors via power supply lines of the light points. A central processing device is provided with warning means to generate a warning if the detected position of the vehicle is outside a predefined area at the airport which is permitted to the vehicle.
A sophisticated control system is utilized in a Space Shuttle Orbiter vehicle. The vehicle uses a conventional type of landing system having an aircraft tricycle configuration consisting of a nose landing gear and a left and right main landing gear. The nose landing gear is located in the lower forward fuselage, and the main landing gear is located in the lower left and right wing area adjacent to the mid-fuselage. The nose wheel is equipped with a ground proximity sensor, in order to determine Weight on Nosegear (WONG), a parameter required during landing. After landing, when WONG and other safety parameters have been established, Nose Wheel Steering (NWS) is enabled. One or more steering position transducers on the nose wheel strut transmit nose wheel steering position feedback to a comparison network so that the nose wheel commanded and actual positions may be compared for position error.
Various means for avoiding collisions of aircraft with ground objects are disclosed in the art.
GB 2408492 to Greene discloses an obstacle avoidance system for a rotary wing aircraft comprising display means, sensing means to determine position, altitude and course, a moving map providing data relating to an area surrounding the aircraft, means for determining/indicating first and second hazardous zones and audible means for indicating an obstacle. The first hazardous zone is a first distance from the aircraft and is represented by a first display color. The second hazardous zone is a second distance, less than the first distance, from the aircraft and is represented by a second display color, indicating greater danger. The audible means may produce audible clicks when the aircraft is within a third distance, also less than the first distance, from an obstacle. The clicks may increase in frequency and volume as the aircraft moves closer to the obstacle. The position sensing means may include a global positioning satellite (GPS) system.
GB 1192273 to Hoban and Smith discloses a terrain avoidance system for an airborne vehicle comprising an intermittently operated, directionally ranging, pulsed energy system for intermittently sensing the position of terrain-obstacles relative to a velocity vector of the vehicle, and a prediction computing means responsive to the information provided by the pulsed energy system and to the inertial motion of the pulsed energy system for predicting the locations of the terrain obstacles relative to the system during intervals between the operations of the intermittently operated pulsed energy system.
EP 1486798 to Mork and Bakken discloses a collision avoidance system comprising comprises a multi-part tubular mast having devices for fixing a solar panel and a radar antenna; an elongate radar antenna in an environment-protective casing, which, with an electronics unit, forms a radar system for synthesized radar detection of an aircraft in a radar coverage area; a central processing unit for identifying on the basis of information from the radar system an aircraft which is in a zone of the radar coverage area and which on the basis of radar information such as direction, distance and/or speed computes a collision danger area; and a high-intensity light system and radio transmitter system that can be activated by the central processing unit upon detection of an aircraft in a collision danger area.
Such collision avoidance methods use light, radar, pulse, or GPS technology to prevent contact of the aircraft with obstacles.
Means for sounding an alarm or stopping movement of a vehicle or moving component upon sensing the presence of, or coming into contact with, an obstacle are disclosed in the art.
In WO02/053413 Buchannan discloses a vehicle having a rear liftgate which employs the sensors used for sensing objects when a vehicle is in reverse to also prevent vehicle damage when the power liftgate is activated. Specifically, the method for sensing an obstruction to the rear of a vehicle comprises the steps of disposing at least one sensor in the liftgate and generating a first signal when the sensor indicates an obstruction when the liftgate is opening. In another aspect of the invention, the method further comprises the step of generating a second signal when the sensor indicates an obstruction when the vehicle is reversing. The apparatus of the present invention comprises at least one sensor disposed in the liftgate and means for generating a first signal when the sensor indicates an obstruction when the liftgate is opening. In another aspect of the invention, the apparatus further comprises means for generating a second signal when the sensor indicates an obstruction when the vehicle is reversing.
GB 1129915 to Narutani discloses a vehicle having one of three ground wheels driven by an electric motor energized through a circuit including a switch operable by a driver. A bumper is elastically mounted on the vehicle frame so as to be displaceable from a normal position upon encountering an obstacle and is so connected with the switch that the switch is opened when the bumper is displaced and cannot be closed until the bumper returns to the normal position.
US 2004/236478 discloses a vehicle including two moving openable members on one side of the vehicle and a single obstruction detector for both of the two openable members. The obstruction detector includes a light sensor that detects light at the closing contact line and an analysis circuit for analyzing the timing of the light received by the sensor. The analysis circuit compares the distribution of the light received by the light sensor to a reference distribution.
In US2004/112662 Hiroyuki and Shigeki disclose a bumper sensor unit. The unit includes a cord-shaped pressure sensitive sensor fixed around a bumper of a running device to detect a contact of an obstacle based on a signal output from the cord-shaped, pressure sensitive sensor. In that case, contact detecting means comprises a filtering section for removing the oscillation frequency component of a contact detecting object from the signal output from the cord-shaped pressure sensitive sensor.
Motor-Generator machines able to provide high torque at low speed, which are compact, are disclosed in the art.
In WO05/112584 Edelson discloses a motor-generator machine comprising a slotless AC induction motor. The motor disclosed therein is an AC induction machine comprising an external electrical member attached to a supporting frame and an internal electrical member attached to a supporting core; one or both supports are slotless, and the electrical member attached thereto comprises a number of surface mounted conductor bars separated from one another by suitable insulation. An airgap features between the magnetic portions of core and frame. Electrical members perform the usual functions of rotor and stator but are not limited in position by the present invention to either role. The stator comprises at least three different electrical phases supplied with electrical power by an inverter. The rotor has a standard winding configuration, and the rotor support permits axial rotation.
In WO2006/002207 Edelson discloses a motor-generator machine comprising a high phase order AC machine with short pitch winding. Disclosed therein is a high phase order alternating current rotating machine having an inverter drive that provides more than three phases of drive waveform of harmonic order H, and characterized in that the windings of the machine have a pitch of less than 180 rotational degrees. Preferably the windings are connected together in a mesh, star or delta connection. The disclosure is further directed to selection of a winding pitch that yields a different chording factor for different harmonics. The aim is to select a chording factor that is optimal for the desired harmonics.
In WO2006/065988 Edelson discloses a motor-generator machine comprising stator coils wound around the inside and outside of a stator, that is, toroidally wound. The machine may be used with a dual rotor combination, so that both the inside and outside of the stator may be active. Even order drive harmonics may be used, if the pitch factor for the windings permits them. In a preferred embodiment, each of the coils is driven by a unique, dedicated drive phase. However, if a number of coils have the same phase angle as one another, and are positioned on the stator in different poles, these may alternatively be connected together to be driven by the same drive phase. In a preferred embodiment, the coils are connected to be able to operate with 2 poles, or four poles, under H=1 where H is the harmonic order of the drive waveform. The coils may be connected together in series, parallel, or anti-parallel.
In US2006/0273686 a motor-generator machine is disclosed comprising a polyphase electric motor which is preferably connected to drive systems via mesh connections to provide variable V/Hz ratios. The motor-generator machine disclosed therein comprises an axle; a hub rotatably mounted on said axle; an electrical induction motor comprising a rotor and a stator; and an inverter electrically connected to said stator; wherein one of said rotor or stator is attached to said hub and the other of said rotor or stator is attached to said axle. Such a machine may be located inside a vehicle drive wheel, and allows a drive motor to provide the necessary torque with reasonable system mass.
In WO2006/113121 a motor-generator machine comprising an induction and switched reluctance motor designed to operate as a reluctance machine at low speeds and an inductance machine at high speeds is disclosed. The motor drive provides more than three different phases and is capable of synthesizing different harmonics. As an example, the motor may be wound with seven different phases, and the drive may be capable of supplying fundamental, third and fifth harmonic. The stator windings are preferably connected with a mesh connection. The system is particularly suitable for a high phase order induction machine drive systems of the type disclosed in U.S. Pat. Nos. 6,657,334 and 6,831,430. The rotor, in combination with the stator, is designed with a particular structure that reacts to a magnetic field configuration generated by one drive waveform harmonic. The reaction to this harmonic by the rotor structure produces a reluctance torque that rotates the rotor. For a different harmonic drive waveform, a different magnetic field configuration is produced, for which the rotor structure defines that substantially negligible reluctance torque is produced. However, this magnetic field configuration induces substantial rotor currents in the rotor windings, and the currents produce induction based torque to rotate the rotor.